JPH08160641A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE: To provide an organic photoreceptor suitable for an electrophotographic device using the wavelength light in the near infrared area as the exposure light, having a stable characteristic in use over a long period, and stably obtaining a good image by containing a specific compound in a charge transfer layer, and adding a specific tocopherol compound. CONSTITUTION: A charge generating layer contains a phthalocyanine compound, a charge transfer layer contains the compound expressed by the formula, I, and the tocopherol compound expressed by the formula I is added to a photoreceptor. In the formulas, R<1> -R<3> indicate the substituted or unsubstituted aryl group, alkyl group, or allylene group, R<4> indicates the hydrogen atom, halogen atom, hydroxyl group, amino group, or alkyl group, R<5> -R<9> indicate the hydrogen atom, halogen atom, hydroxyl group, amino group, or alkyl group. The photoreceptor has high sensitivity for the wavelength light in the near infrared area, the discoloration and deterioration of a coating liquid for the charge transfer layer can be prevented, the liquid life is prolonged, and the characteristic fluctuation of the photoreceptor is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor for electrophotography, and more specifically to a semiconductor laser beam provided with a photoconductive layer having at least a charge generation layer and a charge transport layer containing an organic material as a main component on a conductive substrate. The present invention relates to a laminated type organic photoconductor for electrophotography, which is suitable for an electrophotographic apparatus that uses light having a wavelength in the near infrared region as exposure light, such as a printer.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member has a basic structure in which a photosensitive layer containing a photoconductive material is laminated on a conductive substrate. Inorganic materials such as Se, Se alloys, CdS, and ZnS have been widely used as the photoconductive material, but in recent years, due to the variety of materials and the ability to form a photosensitive layer by a coating method, high productivity can be achieved. Due to its advantages such as thermal stability, heat stability, safety, and flexibility, organic materials are attracting attention, and development and practical application of organic photoconductors having a photosensitive layer containing organic photoconductive material are active. Is being advanced to.

Among them, a so-called laminated type photoreceptor, in which a photosensitive layer is divided into a charge generating layer for receiving light and generating charge carriers and a charge transporting layer for transporting the generated charge carriers, is laminated, It is the mainstream of development because it has the advantage that it can be formed and combined with a material that is most suitable for the above functions and that functional design is easy. In the organic photoreceptor, each constituent layer is usually formed by applying a coating liquid prepared by dispersing and dissolving a functional material and a resin binder in an organic solvent. However, there has been a problem that these coating liquids are deteriorated by exposure to light and deteriorated in color. Further, when the organic photoreceptor is used for a long time under practical conditions, problems such as a decrease in charging potential, an increase in residual potential, and a decrease in sensitivity occur. The cause of these various problems is that the photoconductor is exposed to ozone generated in the charging process and the transfer process by corona discharge in the image forming process in the electrophotographic apparatus,
The exposure to strong external light may be mentioned during maintenance of the electrophotographic apparatus. The influence of these external factors on the above-mentioned various characteristics can be confirmed by an experimental method such as leaving the photoconductor in an ozone atmosphere or irradiating the photoconductor with a strong light of a predetermined amount.

In order to solve the above-mentioned problems, various antioxidants and ultraviolet absorbers have been added to the coating liquid for the photosensitive layer and contained in the photosensitive layer.

[0005]

However, at present, there is no established technology capable of completely solving all of the above problems. The present invention has been made in view of such a situation as described above, in which the photosensitive layer coating liquid is stable, and using such a stable coating liquid, the characteristics are stable even when used for a long period of time. It is an object to be solved to provide a photoconductor suitable for an electrophotographic apparatus, for example, a printer, which can obtain a good image in a stable manner, and which uses light of a wavelength in the near infrared region such as a semiconductor laser light as exposure light. .

[0006]

According to the present invention, the above-mentioned problems are solved in an electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer having a laminated structure including at least a charge generation layer and a charge transport layer. The charge generation layer contains a phthalocyanine compound, the charge transport layer contains at least one compound represented by the following general formula (I), and
The problem is solved by using a photoconductor to which at least one of the tocopherol compounds represented by the following general formula (II) is added.

[0007]

Embedded image

[In the formula (I), R ¹ , R ² and R ³ represent any of a substituted or unsubstituted aryl group, an alkyl group and an arylene group, and R ⁴ represents a hydrogen atom, a halogen atom,
Represents one of a hydroxyl group, an amino group, and an alkyl group].

[0009]

[Chemical 9]

[In the formula (II), R ⁵ , R ⁶ , R ⁷ ,
R ⁸ and R ⁹ represent any one of a hydrogen atom, a halogen atom, a hydroxyl group, an amino group and an alkyl group]. Further, in an electrophotographic photoreceptor comprising a photosensitive layer having a laminated structure comprising at least a charge generation layer and a charge transport layer on a conductive substrate, the charge generation layer contains a phthalocyanine compound,
The charge transport layer contains at least one of the compounds represented by the general formula (I), and has the following structural formula (I
The problem can be solved by providing a photoconductor to which at least one of the compounds represented by II-1) to (III-33) is added.

[0011]

[Chemical 10]

[0012]

[Chemical 11]

[0013]

[Chemical 12]

[0014]

[Chemical 13]

[0015]

Embedded image

Furthermore, in an electrophotographic photoreceptor comprising a photosensitive layer having a laminated structure composed of at least a charge generation layer and a charge transport layer on a conductive substrate, the charge generation layer contains a phthalocyanine compound, The transport layer contains at least one of the compounds represented by the general formula (I), and at least one of the tocopherol compounds represented by the general formula (II) and the structural formula (I
The problem can be solved by providing a photoconductor to which at least one of the compounds represented by II-1) to (III-33) is added.

In the present invention, as the conductive substrate,
For example, an aluminum alloy cylinder, an aluminum vapor-deposited film, or those having an anodized film or a resin film formed on the surface thereof and surface-modified are used. Examples of the resin coating material used for surface modification include insulating polymers such as casein, polyvinyl alcohol, polyamide, melanin and cellulose, conductive polymers such as polythiophene, polypyrrole and polyaniline, or metal oxide powders of these polymers. , Those containing low molecular weight compounds.

The charge generation layer is composed of a charge generation material and a resin binder. As the charge generating material, a phthalocyanine compound is used, and specific examples include the following specific examples (I
Examples thereof include compounds represented by V-1) to (IV-6). Resin binders for the charge generation layer include polycarbonate, polyester, polyamide, polyurethane,
Epoxy, polyvinyl butyral, polyvinyl acetal, phenoxy resin, silicone resin, acrylic resin,
A vinyl chloride resin, a vinylidene chloride resin, a vinyl acetate resin, a homer resin, a cellulose resin, a copolymer thereof, a halide thereof, or a cyanoethyl compound is used.

[0019]

[Chemical 15]

The charge transport layer comprises a charge transport material and a resin binder as main components, and a coating liquid discoloration preventing agent, an antioxidant, or a coating liquid discoloration preventing agent and an antioxidant are added together. It As the charge transport material, at least one of the compounds represented by the general formula (I) according to the present invention is used. Specifically, various hydrazone compounds shown in the following specific examples (I-1) to (I-6) and their derivatives are used alone or in combination. As the resin binder for the charge transport layer, polycarbonate, polystyrene, polyphenylene ether acrylic resin, etc. are used. In particular, when bisphenol A type-biphenyl copolymer polycarbonate is used as the resin binder, the effects of the discoloration preventing agent and the antioxidant of the coating liquid added are remarkable, which is preferable.

[0021]

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[0022]

[Chemical 17]

The compounds represented by the general formula (II) are used as the coating liquid discoloration preventing agent and the antioxidant, and specifically, the compounds shown in the following specific examples (II-1) to (II-4) are used. Can be mentioned. As the antioxidant, the compounds represented by the structural formulas (III-1) to (III-33) are used.

[0024]

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[0025]

[Chemical 19]

[0026]

Since the phthalocyanine compound has sensitivity to light of wavelengths in the near infrared region such as semiconductor laser light, by using the phthalocyanine compound as the charge generating material in the charge generating layer of the laminated type photoreceptor, A photoconductor suitable for an electrophotographic apparatus using, as exposure light, for example, a semiconductor laser printer can be obtained. Further, when the compound represented by the general formula (I) is used as the charge transport material in the charge transport layer and the compound represented by the general formula (II) is added, discoloration deterioration of the coating liquid is prevented, and Ozone deterioration and light deterioration of the obtained photoreceptor can be prevented. In addition, the structural formulas (III-1) to (III) are added to the charge transport layer.
By adding the compound represented by -33), oxidative deterioration of the photoreceptor can be prevented. In the charge transport layer, the compound represented by the general formula (II) and the structural formula (III-
When the compounds represented by 1) to (III-33) are added together, the effect of preventing discoloration deterioration of the coating liquid and ozone deterioration and light deterioration of the photoreceptor as described above is increased.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are schematic cross-sectional views showing the structure of the photoconductor according to the present invention. FIG. 1 shows a negatively charged laminated type photoreceptor having a structure in which a charge generation layer 2 and a charge transport layer 3 are sequentially laminated on a conductive substrate 1, and FIG. 2 shows a positively charged laminated type photoreceptor. It has a structure in which a charge transport layer 3, a charge generation layer 2, and a protective layer 4 are sequentially stacked on top. The protective layer 4 is provided to protect the charge generation layer 2 which is a thin film. The following example describes the case of the negatively charged laminated type photoreceptor shown in FIG. 1, but the present invention is not limited to this.

Example 1 On the outer peripheral surface of an aluminum alloy cylinder having an outer diameter of 60 mm, a length of 310 mm and a wall thickness of 1 mm, a polyamide having a number average molecular weight of 100,000 (manufactured by Daicel-Huls Co., Ltd .; trade name "T17") was used.
1 ") 4 parts by weight and styrene-maleic acid resin (BASF
Japan Ltd. Made; Product name "Supra Pearl A
P ") 1 part by weight is dissolved in a mixed solvent of 200 parts by weight of methanol and 100 parts by weight of 1-butanol to prepare a resin film coating solution, which is applied by dip coating to form a resin film having a thickness of 0.1 .mu.m. As a base material.

On this conductive substrate, 5 parts by weight of the metal-free phthalocyanine shown in Specific Example (IV-1) as a charge generating material and polyvinyl acetal as a resin binder (manufactured by Sekisui Chemical Co., Ltd .; trade name " S-REC KS-
1) 5 parts by weight was mixed with 700 parts by weight of dichloromethane, and the coating solution prepared by kneading with a mixer for 3 hours was applied by dip coating to form a charge generation layer having a thickness of 0.3 μm.

On this charge generation layer, 1000 parts by weight of the compound shown in Specific Example (I-3) as a charge transport material and bisphenol A-biphenyl copolymerized polycarbonate as a resin binder (manufactured by Idemitsu Kosan Co., Ltd .; Product name "B
P-Pc ") 1000 parts by weight, 20 parts by weight of the compound shown in Specific Example (II-1), and the structural formula (I
A coating solution prepared by dissolving 50 parts by weight of the compound shown in II-16) in 7,000 parts by weight of dichloromethane was applied by dip coating to form a charge transport layer having a film thickness of 20 μm, to obtain a photoreceptor.

Example 2 A photoconductor was prepared in the same manner as in Example 1 except that the charge transport material used in the charge transport layer was changed to the specific example (I-1). Example 3 A photoconductor was produced in the same manner as in Example 1 except that the charge transport material used in the charge transport layer was changed to the specific example (I-2).

Example 4 Example 1 was repeated except that the compound of Example (II-1) compounded in the charge transport layer coating solution was replaced with the compound of Example (II-3). A photoconductor was prepared in the same manner. Example 5 Same as Example 1 except that the compound compounded as an antioxidant in the coating liquid for charge transport layer was changed from Structural Formula (III-16) to Structural Formula (III-1). Then, a photoconductor was prepared.

Example 6 Example 6 is different from Example 2 except that the compound compounded as an antioxidant in the charge transport layer coating solution is changed from Structural Formula (III-16) to Structural Formula (III-20). A photoconductor was prepared in the same manner as in 2. Example 7 In Example 1, the resin binder of the charge transport layer was bisphenol Z-type polycarbonate (Mitsubishi Gas Chemical Co., Inc.).
Manufactured: A photoconductor was manufactured in the same manner as in Example 1 except that the product name was changed to "PCZ300".

Example 8 In Example 1, the resin binder of the charge transport layer was bisphenol A type polycarbonate (manufactured by Teijin Chemicals;
A photoconductor was produced in the same manner as in Example 1 except that the trade name "Panlite L-1225") was used. Example 9 In Example 1, the coating solution for the charge transport layer was added to the structural formula (II
A photoconductor was prepared in the same manner as in Example 1 except that the compound shown in I-16) was not added.

Example 10 In Example 1, a specific example of the coating liquid for the charge transport layer (II
A photoconductor was produced in the same manner as in Example 1 except that the compound shown in -1) was not added. Example 11 In Example 2, the coating liquid for the charge transport layer was added with the structural formula (II
A photoconductor was prepared in the same manner as in Example 2, except that the compound shown in I-16) was not added.

Example 12 In Example 2, a specific example (II
A photoconductor was produced in the same manner as in Example 2 except that the compound shown in -1) was not added. Example 13 In Example 7, a specific example (II
A photoconductor was prepared in the same manner as in Example 7, except that the compound shown in -1) was not added.

Example 14 In Example 8, the charge transporting layer coating solution was added with the structural formula (II
A photoconductor was prepared in the same manner as in Example 8 except that the compound shown in I-16) was not added. Comparative Example 1 In Example 1, a specific example (II
A photoreceptor was produced in the same manner as in Example 1 except that the compound shown in -1) and the compound shown in Structural Formula (III-16) were not blended.

For the purpose of investigating discoloration deterioration due to light of the charge transport layer coating solutions used in the above-mentioned Examples and Comparative Examples,
The coating solution was irradiated with white light of 1000 lux for 24 hours, and the degree of discoloration was visually compared. Further, the electrophotographic characteristics of each of the photoconductors of the above-mentioned examples and comparative examples were evaluated. Each photoconductor is mounted on a semiconductor laser printer with fixed output of the charging mechanism, exposure mechanism, and static eliminator, and printing is performed on 50,000 A3 sheets in an atmosphere of normal temperature and normal humidity (temperature 20 ° C, relative humidity 60%). A running test was performed, and the initial white paper potential V _w , the black paper potential V _{b at the start} of running, and the variations ΔV _w and ΔV of these potentials due to the running test of 50,000 sheets.
_b was measured.

Further, for the purpose of evaluating ozone resistance, each photoreceptor was exposed to an environment of ozone concentration of 100 ppm for 4 hours, and the half-attenuated exposure amount before and after the exposure was measured. Furthermore,
For the purpose of evaluating the resistance to strong light fatigue, each photoconductor was irradiated with white light of 1000 lux for 1 hour, and under a constant charging condition, the initial charge position V _s before the irradiation and the charge position change amount ΔV _s after the irradiation were measured. Was measured.

Table 1 shows the evaluation and measurement results.

[0041]

[Table 1]

As can be seen from Table 1, each of the photoreceptors of Examples and Comparative Examples contains phthalocyanine as the charge generating material of the charge generating layer and is represented by the general formula (I) as the charge transporting material of the charge transporting layer. Since the compound is contained, the initial characteristics are good, the half-attenuation exposure amount to the semiconductor laser light is small, and the sensitivity is excellent. The tocopherol compound represented by the general formula (II) and the structural formulas (III-1) to
Examples 1 to 3 containing the compound shown in (III-33)
Each of the photoconductors 8 has no discoloration due to light exposure of the charge transport layer coating liquid, and is stable with little variation in the characteristics of the photoconductors due to running test, ozone exposure, and intense light irradiation. In the photoreceptor of Comparative Example 1 containing neither the tocopherol compound represented by the general formula (II) nor the compounds represented by the structural formulas (III-1) to (III-33), the coating liquid for the charge transport layer was exposed to light. Discoloration occurs, and the characteristic changes of the photoreceptor due to running tests, ozone exposure, and intense light irradiation are extremely large. In each of the photoconductors of Examples 9, 11, and 14 containing the tocopherol compound represented by the general formula (II), no color change was observed due to light exposure of the charge transport layer coating solution, and a running test and ozone were performed. The characteristic variation of the photoreceptor due to exposure and intense light irradiation is smaller than that of the photoreceptor of Comparative Example 1. In each of the photoconductors of Examples 10, 12, and 13 containing the compounds represented by the structural formulas (III-1) to (III-33), there is discoloration due to the light exposure of the charge transport layer coating solution. In comparison with the photoconductor of the comparative example, the characteristics of the photoconductor due to running test, ozone exposure, and intense light irradiation are smaller. The tocopherol compound represented by the general formula (II) or / and the structural formulas (III-1) to (II) in the charge transport layer.
The effect of adding the compound shown in I-33) is clear.

As can be seen from the results of the photoconductors of Examples 1 and 7, 8 the photoconductors using bisphenol A type-biphenyl copolymerized polycarbonate as the resin binder of the charge transport layer have excellent stability. .

[0044]

According to the present invention, in a photoconductor for electrophotography comprising, on a conductive substrate, a photosensitive layer having a laminated structure including at least a charge generation layer and a charge transport layer, a phthalocyanine compound is contained in the charge generation layer. At least one of the compounds represented by the general formula (I) is contained in the charge transport layer, and at least one of the tocopherol compounds represented by the general formula (II) is added as an additive. Or the structural formula (III-
1) to (III-33), or at least one of the tocopherol compounds represented by the general formula (II) and the structural formulas (III-1) to (III-). 33) and at least one of the compounds shown in 33) are added.

By containing a phthalocyanine compound in the charge generation layer and at least one of the compounds represented by the general formula (I) in the charge transport layer, light having a wavelength in the near infrared region such as a semiconductor laser can be obtained. A high-sensitivity photoconductor can be obtained. In addition, the charge transport layer may have the general formula (II)
By adding the tocopherol compound represented by the formula (4), it is possible to prevent discoloration and deterioration of the coating liquid for the charge transport layer, the liquid life is extended, and fluctuations in the photoreceptor characteristics are reduced. Further, the structural formulas (III-1) to (III-3
Addition of at least one of the compounds shown in 3) reduces the fluctuation of the photoreceptor characteristics. Further, at least one tocopherol compound represented by the general formula (II) and the structural formulas (III-1) to (III-
By adding at least one of the compounds represented by 33), discoloration and deterioration of the charge transport layer coating liquid can be prevented, and fluctuations in the photoreceptor characteristics can be significantly reduced.

As described above, according to the present invention, the wavelength is in the near-infrared region such as a semiconductor laser beam, which has stable characteristics even when continuously used for a long period of time and a good image can be stably obtained. It is possible to obtain an electrophotographic photosensitive member suitable for an electrophotographic apparatus such as a printer that uses light as exposure light.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an embodiment of a photoconductor according to the present invention.

FIG. 2 is a schematic cross-sectional view showing the constitution of another embodiment of the photoconductor according to the present invention.

[Explanation of symbols]

 1 Conductive Substrate 2 Charge Generation Layer 3 Charge Transport Layer 4 Protective Layer

Claims (3)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer having a laminated structure comprising at least a charge generation layer and a charge transport layer on a conductive substrate, wherein the charge generation layer contains a phthalocyanine compound, An electron characterized in that the layer contains at least one of the compounds represented by the following general formula (I), and at least one of the tocopherol compounds represented by the following general formula (II) is added. Photoreceptor for photography. Embedded image [In the formula (I), R ¹ , R ² and R ³ represent any of a substituted or unsubstituted aryl group, an alkyl group and an arylene group, and R ⁴ represents a hydrogen atom, a halogen atom, a hydroxyl group or an amino group. , Represents any of alkyl groups]. Embedded image [In the formula (II), R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ represent any one of a hydrogen atom, a halogen atom, a hydroxyl group, an amino group and an alkyl group]. 2. An electrophotographic photoreceptor comprising a photosensitive layer having a laminated structure comprising at least a charge generation layer and a charge transport layer on a conductive substrate, wherein the charge generation layer contains a phthalocyanine compound, The layer contains at least one of the compounds represented by the general formula (I), and the following structural formulas (III-1) to (III-33)
An electrophotographic photoreceptor comprising at least one compound represented by the formula (1). Embedded image [Chemical 4] Embedded image [Chemical 6] [Chemical 7] 3. An electrophotographic photoreceptor comprising a photosensitive layer having a laminated structure comprising at least a charge generation layer and a charge transport layer on a conductive substrate, the charge generation layer containing a phthalocyanine compound, The layer contains at least one of the compounds represented by the general formula (I), and at least one of the tocopherol compounds represented by the general formula (II) and the structural formula (III-1).
To (III-33) to which at least one of the compounds is added.